Efficacy of Landmark-Guided Transverse Abdominis Plane (LTAP) Block in Pediatric Patients Undergoing Laparoscopic Appendectomy.

INTRODUCTION: Optimizing perioperative analgesia in patients undergoing abdominal surgery remains a challenge given the side effects of narcotics and the potential for abuse. While transversus abdominis plane block has been shown to improve clinical outcomes, such as decreased opioid consumption and pain scores among adult patients, there is limited data regarding its efficacy for pediatric patients. This study evaluates efficacy amongst pediatric patients undergoing landmark-guided transversus abdominis plane (LTAP) during laparoscopic appendectomy. METHODS: A retrospective chart review of patients, ages 0-18 years old, who underwent laparoscopic appendectomy for uncomplicated appendicitis at a single institution from January 2021 to December 2022 was conducted. Pearson's chi-square test or Fisher's exact test and Welch's t test were used to assess differences between the two cohorts for categorical and continuous variables, respectively. Results are statistically significant at P < .05. RESULTS: Of the 90 patients who met inclusion criteria, 40% (n = 36) underwent LTAP block. Those with LTAP block had a shorter average operative time than those without LTAP block (.6 vs .7 hours; P = .009). Similarly, patients with LTAP block had a shorter average time to discharge (4.1 vs 11.0 h; P = .039). There were no other statistically significant differences in postoperative outcomes including narcotic use between both cohorts. DISCUSSION: Landmark-guided transversus abdominis plane blocks did not increase operative times yet reduced time to discharge for pediatric patients who underwent laparoscopic appendectomy at our institution. Larger studies are needed to evaluate the relationship between LTAP administration and postoperative narcotic consumption to make clinical recommendations.

Precisely timed theta oscillations are selectively required during the encoding phase of memory.

Brain oscillations have been hypothesized to support cognitive function by coordinating spike timing within and across brain regions, yet it is often not known when timing is either critical for neural computations or an epiphenomenon. The entorhinal cortex and hippocampus are necessary for learning and memory and exhibit prominent theta oscillations (6-9 Hz), which are controlled by pacemaker cells in the medial septal area. Here we show that entorhinal and hippocampal neuronal activity patterns were strongly entrained by rhythmic optical stimulation of parvalbumin-positive medial septal area neurons in mice. Despite strong entrainment, memory impairments in a spatial working memory task were not observed with pacing frequencies at or below the endogenous theta frequency and only emerged at frequencies ≥10 Hz, and specifically when pacing was targeted to maze segments where encoding occurs. Neural computations during the encoding phase were therefore selectively disrupted by perturbations of the timing of neuronal firing patterns.